Typewriter



.U 19,1935. R. G. THOMPSON ET AL 994,544

TYPEWRITER Filed March 13, 1950 2 Sheets-Sheet 1 INVENTOR S THEIR ATI'ORNEY March 19, 1935. R. G. THOMPSON ET AL 3 5 TYPEWRI'TER Filed Ma rch 13, 1930 2 sheet -sheet 2 INVENTORS Fusseilm Zkpsqn ofldgfiegzrg Cmzmrin v TH EIR ATTORNEY 7 Patented Mar. 19, 1935 PATENT OFFICE TYPEWRITER Russell G. Thompson and Chester W. 'Cru'mrlne, Rochester, N. Y.,- assignors to Electromatlc Typewriters, Inc, Rochester, N. Y., a corporation of New York Application March 13, 1930, Serial No. 435,472

20 Claims. (Cl, 19785) This invention relates to improvements in typewritmg machines, and especially to escapement mechanism for controlling the movement of the carriage for letter and word spacing.

- The principal object of the invention is to provide a simple and inexpensive device of this kind which is rapid in operation and positive in action.

A further object of the invention is to provide a device of this kind in which the pawls directly engage a ratchet, means being provided for alternately actuating the pawls to release the carriage and permitting it to move forwardly one letter space each time one or the other of the pawls is actuated. 1

Another object of the invention is to provide an escapement mechanism having two pawls which alternately engage a ratchet or rack on the carriage for retaining or stopping it in letter printing position.

A further object of the invention is to providea device of this kind having two pawlgadapted to engage a rack and alternately movable into the path of a movable device for disengaging them from the rack.

A still further object of the invention is to provide a device of this kind in which a pair of pawls alternately engagea ratchet to stop the movement of the carriage in letter spacing, said pawls being resiliently mounted to absorb the shock of impact with the ratchet.

To these and other ends, the invention consists in the construction and arrangement of parts that will appear from the following description when read in conjunction with the accompanying drawings, thenovel features being pointed out in the claims following the specification.

In the drawings:

Figure 1 is a fragmentary transverse section through the carriage and keyboard of atypewritmg machine showing one embodiment of the invention applied thereto;

Figure 2 is a fragmentary plan view of the escapement devices;

Figure 3 is a rear elevation of the same;

Figure 4 is an inverted plan view;

Figure 5 is a section taken substantially on line 5-5 of Figure 1 looking to the left from said line;

Figure 6 is a detail plan view of the pawls;

Figure '7 is a rear elevation of 'the same, and

Figures 8, 9 and are plan views illustrating successive steps in the operation of the escapement.

Referring particularly to the drawings, in which like reference numerals refer to the same parts in all figures, 1 represents a guideway fixed in the front of the frame of the machine and cooperating with the guideway 2 fixed in the rear of the frame for movably supporting a carriage-3 on which the platen and paper feeding devices of the typewriting machine are mounted, as usual -5 in the art.

The carriage is provided with guideways 4 cooperating with the guideways 1 and 2 to form raceways for the retention of roller bearings 5 on which the carriage moves transversely of the 10 machine for effecting letter spacing. Pivotally mounted in the frame of the machine are the key levers 6. operatively connected with type bars adapted to cooperate with the platen in the operation of printing. A spring motor 18 is con nected with the carriage for moving it in letter spacing direction, and escapement devices cooperate with the carriage for stopping it after each successive letter space movement.

The improved escapement devices illustrated in the drawings are of the same character as those disclosed but not claimed in an application for patent filed by Chester W. Crumrine, on or about July 25, 1929, Serial No. 381,016, now Patent No. 1,837,898, dated December 22, 1931, and comprise a rack or ratchet bar 6 secured to the carriage to move therewith. A pair of pawls 'l and 8 are pivotally mounted on the frame and arranged to engage said rack alternately to stop the carriage after each successive letter space movement. A pawl-releasing device in the form of a trip lever 9 is pivoted in the frame and arranged to engage said pawls alternately for disengaging them from the rack. The lever 9 is connected by means of a link 10 with one arm of a bell crank 11 pivoted in the frame, the other arm of which is connected by means of a link 12 with a swinging universal bar 13 arranged under the key levers 6 and adapted to be actuated thereby. A spring 14 is connected at one end to the lever 9 and at its other end to the frame of the machine, and serves to resiliently maintain the lever 9 and parts connected therewith in the normal position shown in Figure 1. The pawls 7 and 8 are pivoted on a stud 15 carried on a .bracket 16 secured to the frame preferably by means of headed screws 1'7.

As shown in the drawings, the bracket 16 is secured to the rear of the frameof the machine and curves rearwardly and downwardly and then inwardly to a point adjacent the rack on the carriage and forms, in effect, a gooseneck with the stud 15 on the inwardly projecting arm. By this construction, the pawls are mounted on a comparatively'long arm which being resilient serves to absorb the shock of impact between the rack and pawls, thus reducing noise and securing a more positive action without rebound.

Each of the pawls '7 and 8 is provided with an opening 19 elongated in the direction of the rack or movement of the carriage whereby they are pivoted on the stud 15 to afford a limited longitudinal movement thereon, substantially equal to one-half the unit letter space movement of the carriage. The pawls are separated from each other by means of a washer arranged between them on the stud and formed in the end of an arm 20 secured to the bracket 16 and projecting forwardly therefrom in spaced relation thereto.

The carriage motor tends to move the carriage and with it the rack 6 to the left of the operator, or to the right, as seen from the rear in the drawings. The teeth 27, 28 of the rack are spaced two letter-space distances apart and are engaged alternately by the pawls 7 and 8 to stop the movement of the carriage between successive letter-space movements, or after each half tooth movement of the rack. The pawls are similar in construction; however, the upper one '7 in the embodiment illustrated is substantially one letter space shorter than the lower one 8, so that when in operative engagement with the rack, its tooth is advanced one and one-half letter space beyond the tooth of the longerpawl 8.

The pawls 7 and 8 are provided with rearwardly extending arms 22 and 23 respectively, each having an opening 24 therein. Coiled springs 25 and 26 each have one end connected to a pawl or an arm 22 or 23 thereon, and at their other ends are anchored to the frame of the machine. These springs tend to move the pawls bodily rearwardly to the left, as seen in the drawings, over the rack until the pivot stud 15 engages the ends of their slots, when they swing on the pivot into engagement with the rack.

When the parts are in the position shown in Figure 8 of the drawings, the pawl 7 engages the tooth 2'1 of the rack and the stud 15 engages the left-hand end of its opening 19 and maintains the carriage at rest against the action of its spring. At this time, the pawl 8 rests idly against the rack or the rear side of the tooth 2'7, and the stud 15 engages the right hand endof its opening under the action of its spring 26. At this time, the pawl 8 maybe said to be in rack-engaging position. When the universal bar is now actuated, the lever 9 engages the right hand end of the pawl 7 to move it on its pivot against the action of its spring 25 and out of engagement with the rack. During this movement, the lever 9 passes idly past the end of the pawl 8, which has been moved to its extreme left position with its right end out of the path of the lever. When the pawl 7 disengages the rack, the carriage spring or motor moves the carriage and with it the rack until the rack or the tooth 28 thereon engages the pawl 8 a distance of substantially one-half letter space. The carriage spring is relatively stronger than the springs 25 and 26, and hence moves the en-' hali letter-space distance, and the pawl then moves with the rack on the stud 15 until the end of itsv slot is reached, a further distance of substantially one-half letter space when further movement of the carriage is arrested thereby. The movement of the pawl 8 with the rack moves its right hand end into the path of the lever 9 to be actuated thereby'at its next actuation. Under the influence of its spring, the pawl 7 moves to the left, as seen in the drawings, over the tooth 2'7 of the rack and into contact with the rack the lever 9. Upon the next actuation of the lever 9, the pawl 8 is actuated out of engagement with the rack, permitting the rack and carriage'to advance another letter-space, the parts coming to rest in the position shown in Figure 8 but with the pawl 7 in engagement with the tooth 28. The teeth of the rack are two letter-space distances apart, so that the rack advances only one-half tooth distance with each actuation of the lever 9. Since the pawls are not arranged in the same plane, the rack is at least twice as thick as the pawls, thus securing greater strength and rigidity.

The lever 9 is loosely mounted on a stud 29 and resiliently held against lateral movement on the stud by means of a spring 30 coiled about the stud and engaging the lever. By this construction, the lever has a limited lateral swinging movement on its pivot against the resiliency of the spring with the carriage when struck by the end of a pawl.

It will be noted that the full letter space movement of the carriage is free to take place whenever a key is depressed to actuate the lever 9. Even if the key is held depressed, the carriage moves the full letter space distancebefore again coming to rest, and the engagement of the forwardly moving pawl with the lever swings the lever on its pivot until the pawl engages the stud 15. It will also be noted that the carriage is always free to move in a reverse direction to begin a new line, since the ratchet teeth engage the pawls to move them on their pivots out of engagement therewith.

The ratchet teeth on the rack are formed substantially on the radius of a circle having the pivotal axis of the engaging or. holding pawl '7, as seen in Figure 8, as its center, so. that the pawl moves freely from the rack and there is no binding or reverse movement of the carriage when the pawl is disengaged from the rack, since the pawl moves directly along the plane of the surface of the tooth. The relative difference in length between the two pawls, compared with the radius of this circle, is so small that the pawl 8 operates in substantially the same manner. It will be noted that the carriage motor tends to move the pawl which engages the rack against its pivot, which is as near as possible to the rack, so that the action of the carriage more forcibly engages "the pawl with the rack.

Although only one embodiment of the invention is described herein, it will be understood that this application is intended to cover such changes or modifications as may come within the spirit of the invention or scope of the following claims.

, We claim:

1. In 'a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a rack on the carriage, a pair of pawls slidably mounted on a common pivot, one of said pawls being of greater length than the other to engage the' rack at a greater distance from the pivot, means forindependently moving said pawls in one direction on their pivot and swinging them into engagement with the rack, and means for alternately disengaging-said pawls from the rack.

2. In a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a rack on the carriage, a pair of pawls slidably mounted on a common pivot and adapted to engage said rack at two points separated less than a racktooth distance apart, resilient means for moving said pawls into engagement with said rack, and means for disengaging one of said pawls from the rack while the other engages the rack to arrest the movement of the carriage.

3. In a typewriting machine, a combination'of a frame, a carriage movable thereon, means for moving the carriage, a rack on the carriage, a trip lever pivoted on the frame, a pawl pivoted on the frame and adapted to engage the rack and move with it on its pivot into the path of said trip lever, means for actuating the trip lever for disengaging said pawl from the rack, resilient means for moving said pawl out of the path of the trip lever when disengaged from the rack, and a second pawl pivoted on the frame adapted to be engaged by the rack and moved into the path of the trip lever when the first pawl is operatively disengaged from the rack.

4. In a typewriting. machine, the combination of a frame, a carriage movable thereon, means for moving the carriage for letter spacing, a pair of pawls mounted on the frame and movable into and out of engagement with the rack and also having a limited movement with the rack, a trip lever movable into the path of the pawls for disengaging them from the rack and movable in the direction of movement of the pawls when engaged thereby, and resilient means for maintaining said lever in normal position.

5. In a typewriting machine, the combination with a frame and a carriage movable thereon, of a rack fixed on the carriage, a pair of pawls pivoted on the frame and movable independently of each other in the plane of the rack to and from engagement therewith, resilient means for moving said pawls longitudinally of the rack andinto engagement therewith, said pawls being movable against the tension of said resilient means by the rack, and means for moving said pawls alternately and independently of each other out of engagement with said rack.

6. In a typewriting machine, the combination with a frame, a carriage movable thereon for letter spacing, a rack on the carriage having teeth spaced two letter space distances apart, a pair of pawls pivoted on the frame and movable bodily thereon in the direction of carriage movement a distance of substantially one-half letter space, means for moving said pawls bodily and swinging them into engagement with the rack, and means for moving said pawls alternately from engagement with the rack to release it for letter spacing.

'7. The combination with a frame, a carriage movable thereon for letter spacing, a ratchet bar ing arranged to swing on their pivot in the plane of the ratchet bar to and from engagement there' with, separate means for moving said pawls bodily in one direction relatively to the ratchet and swinging them into engagement therewith,

one of said pawls being adapted to operatively engage a tooth of the ratchet while the other rests idly in engaging position, and a lever movable transversely of said pawls into engagement with the pawl which operatively engages the rack for moving said pawl out of operative engagement with said tooth while the ratchet moves with the carriage into operative engagement with the other pawl.

8. The combination with a frame, a carriage movable thereon for letter spacing, a ratchet bar fixed on the carriage and extending longitudinally thereof, means for moving the carriage, a pair of pawls pivoted on a common pivot and slidable thereon in a direction longitudinally of the ratchet and adapted to engage it at diflferent points, means for separately sliding said pawls on their pivot in one direction and swinging them on the pivot into engagement with the ratchet, and means for alternately disengaging the pawls from the ratchet.

- 9. The combination with a frame, of a carriage movable thereon for letter spacing, means for moving the carriageja rack fixed on the carriage and movable therewith, a pawl slidably mounted on a pivot on the frame and engaging the rack to arrest the movement of the carriage, a second pawl movable on the frame, resilient means for moving the second pawl into position to engage the rack and arrest the carriage when the first mentioned pawl is disengaged therefrom, a lever movable transversely of said pawls into engagement with the pawl which operatively engages the rack for moving the first pawl from operative engagement with the rack to release the carriage, and resilient means for sliding said first pawl on its pivot longitudinally of the rack and swinging it to rack-engaging position.

, 10. The combination with a frame, of a carriage movable thereon, means for moving the carriage for letter spacing, a rack on the cariage, a pawl pivoted on the frame and engaging the rack to hold the carriage against movement under the action of its moving means, releasing means for disengaging the pawl from the rack to permit movement of the carriage, means for moving the pawl longitudinally of the rack when disengaged therefrom and out of the path of said releasing means, and a second pawl pivoted on the frame and slidable on the frame in letter-space direction and arranged to be engaged by the rack, when the rack is released by the first pawl, and moved thereby into the path of the releasing means.

11. The combination with a frame, of a carriage movable thereon, means for moving the carriage for letter spacing, a rack on the carriage, a pair of .pawls mounted on the frame and movable into and out of engagement with the rack and also having bodily movement in a direction longitudinally of the rack, resilient means for moving eachof said pawls longitudinally of the rack when disengaged therefrom, a trip lever movable into alternate engagement with the pawls for disengaging them from the rack, a bell crank lever operatively connected with the trip lever, and a universal bar operatively connected with said bell crank lever.

12. The combination with a frame and a carriage movable thereon, of a rack fixed on one of said parts, apair of pawls pivoted on the other of said parts and movable independently of each other in the plane of said rack to and from engagement therewith, said pawls being slidable on their pivots in a direction longitudinally of the rack, resilient means for moving said pawls longitudinally of the rack and into engagement therewith, and means for moving said pawls alternately and independently of each other out of engagement with said rack.

13. The combination with a frame, of a carriage movable thereon for letter spacing, a rack on the carriage, a trip device movable in a plane arranged transversely to the rack, a pair of pawls on the frame independently movable into engagement with the rack and by the rack into the plane of movement of said trip device'to be disengaged from the rack thereby, and means for moving said pawl from the plane of movement of said trip device when disengaged from the rack.

14. The combination with a frame, of a carriage movable thereon for letter spacing, a rack on the carriage, a pair of pawls pivoted on the frame and movable bodily thereon longitudinally of the rack a distance less than a letter space and one of said pawls being substantially a letter space longer than the other to engage the rack at a more remote distance from the pivot of the pawls, means for moving said pawls alternately end of a letter space movement, both of said pawls being mounted for bodily movement endwise of the rack and one being located in advance of the other, and a lever movable transversely of said pawls and into engagement with whichever pawl lies in the path of said lever to disengage said pawl from the rack.

16. In a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a

' rack on the carriage, a pair of pawls pivotally their pivot and swinging them into engagement with the rack, and means for alternately disenag ng the pawls from therack.

17. In a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a rack on the carriage, a pair of pawls pivotally mounted .ona common axis extending transversely of the rack and supported on the frame, said pawls having a limited slidable movement on said axis in a direction transversely thereof and acting to simultaneously engage and rest against respectively adjacent tooth faces of said rack at different points endwise of the rack, and means for alternately disengaging the pawls from the rack. 18. In a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a rack on the carriage, a pair of pawls pivotally mounted on a common axis extending transversely of said rack and supported on the frame, said pawls having a limited slidable movement on said axis in a direction transversely thereof and acting simultaneously to engage and rest against respectively said rack at different points separated endwise of the rack by a distance of less than one rack tooth, resilient means for moving the pawls into engagement with the rack, and means for alternately disengaging the pawls from the rack.

19. In a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a rack on the carriage, a pair of pawls pivotally mounted on a-common axis extending transversely of the rack and supported on the frame, said pawls having limited slidable movement transversely of I said axis and being engageable with and resting against respectively the rack at different points endwise thereof, the pawls acting alternately to engage successive teeth of the rack and thereby stop its movement, means for independently moving the'pawls into engagement with the rack, and means for alternately disengaging the pawls from the rack.

20. In a typewriting machine, the combination of a frame, a carriage movable thereon for letter spacing, means for moving the carriage, a rack on the carriage, a pair of pawls pivotally mounted on a common axis extending transversely of the rack and supported on the frame, said pawls having a limited slidable movement transversely of said axis and one of the pawls being of greater length than the other and thereby engageable with the rack at a point in advance of the other pawl, means for independently moving the pawls into engagement with the rack, and a lever movable transversely of the pawls and into engagement with whichever pawl lies in the path of said lever to disengage said pawl from the rack,- the pawls alternately engaging successive teeth of the rack to stop its movement and being alternately moved into the path of said lever.

RUSSELL G. THOMPSON. CHESTER w. CRUMRINE. 

